[Glastonbury] Sound

[tim hall]

Last Monday 16 August 2004 23:40, nick irwin was like:
> I am running Mandrake 10.0, using the ALSA sound system on the 2.6 kernel.
> Sound is all fine and good except that when I start up a second x-windows
> session, no sound.

I confess to having little experience of Mandrake or Artsd, or indeed 2.6 
kernels, so I'm not sure how much use I'm going to be. A second X-session? 
different user? how are you achieving this? I assume that both users and the 
devices /dev/dsp* /dev/mixer* are all members of the 'audio' group or 
whatever MDK calls it. Usual permissions are 660, which should be open enough 
in most circumstances.

> The arts sound daemon is being used, someone told me it was a bad thing to
> have running but I can't stop it being used without killing off sound
> altogether.

It used to conflict with ALSA completely, Artsd now has ALSA support, it may 
be limited, however. Stopping it shouldn't kill the sound, this suggests to 
me that ALSA isn't set up properly. It would be useful to see your ALSA 
configuration (mine's in /etc/alsa/modultils/1.0, but I think Mandrake puts 
it somewhere else) and each user's .asoundrc just in case there is anything 
obvious there.

> both accounts can use sound when they are the only ones running, but it
> seems that the first account that is logged into locks a file or resource
> and no other account can use the sound.

That sounds like a reasonable explanation. This is normal.
Are you familiar with
 http://alsa.opensrc.org/
Often this provides more useful information than  http://www.alsa-project.org 
there is a useful debugging script available at:
http://alsa.opensrc.org/?aadebug which might also turn up some useful info.

> Oh and the error message is:
>
> Device /dev/dsp can't be opened (permission denied)

Ah. /dev/dsp can only be used by one application at a time, which locks it 
against all other applications. I would guess that your other user would have 
to be using the same instance of Artsd or Jackd. I don't know how you achieve 
that. Either that or you have to stop the first user's sound server and 
enable the second. Would that work?

Does this mean you are running two whole versions of KDE on the same box?!? 
Although this shouldn't make any difference with a properly set up ALSA, you 
would be better off with a lighter weight WM, but obviously you won't be able 
to use artsd then as it's KDE specific.

This is a rather longwinded blind stag in the dark.
Why do you need both users to have access to the soundcard at once, if it's 
not a rude question ?;-)

Let us know how you get on.

cheers

tim hall